Numerous speed change mechanisms including those which employ oppositely stepped pulleys and coacting transmission belts are known in the prior art. The general objective of this invention is to improve on the prior art particularly in terms of a belt shifting arrangement to effect a desired speed change with convenience, reliability and safety.
Another important object of the invention is to provide a speed change mechanism for belt and pulley variable speed transmissions which is highly simplified, durable and inexpensive to manufacture.
Another object is to provide a speed change mechanism having automatic safety locking means to prevent shifting of the transmission belt while it is actively engaged with chosen complementary stepped portions of the multiple diameter transmission pulleys.
An object of the invention is to provide a speed change mechanism of the mentioned type ideally suited for driving the spindle of a drill press but also capable of transmitting variable speed rotation to a wide variety of driven devices.
Still another object is to provide a speed change mechanism which is highly compact.
Other features and advantages of the invention will become apparent during the course of the following description.